This invention relates generally to suction fittings for use with water-circulating pumps in spas and tubs. More particularly, the invention relates to suction fittings having safety features that minimize problems of personal injury and damage to equipment.
Hot tubs and spas are generally equipped with pumps for the circulation of water. Although these circulating pumps may be run indefinitely, most use a timer for safety reasons, and some use a level sensor to preclude their operation when the water level is low. Without the use of automatic shutoff devices, a circulating pump may be damaged by continuous operation. For example, a condition such as low water level could cause the pump to burn out or cause water jets to spray out of the tub area. A related difficulty is that a person entering or leaving the tub or spa causes undesirable changes in the water level. Too high a level may result in overflow of the tub. Too low a level may uncover the water jets. The use of a timer to control operation of the pump does not adequately address these problems.
Some tubs or spas use a level sensor to control the operation of the pump. A hole is required to be drilled in the wall of these tubs or spas and a fitting installed for connection to the sensor by means of a hose. Use of a fitting of this general type increases the chance of leaks, since an additional hole is needed for installation. Another drawback of level sensors is that they become inoperative if the hose becomes dislodged from the fitting.
An even more important problem with suction fittings arises when the fitting itself becomes blocked. Foreign objects, such as hair, skin or some other part of a person positioned near or leaning against the fitting can cause a permanent or temporary blockage, during which the pump will operate unsafely. Blocking the suction fitting with hair or the body can cause serious personal injury or death. Although suction fittings are designed to operate safely within a rated flow range, if that flow range is exceeded entrapment of the hair or part of the body can occur. Using a timer or level sensor will not alleviate this problem.
The invention described and claimed in the cross-referenced application overcomes many of the drawbacks discussed above, and operates satisfactorily in most situations. The present invention is concerned with further improvements in suction fittings of the same general type.